Do I need to have my hands free to understand hand-related language? Investigating the functional relevance of experiential simulations.

Theories of embodiment state that people mentally simulate the described situations and events during language comprehension. While several studies have provided evidence that these simulations exist, it is still unclear whether they are functionally relevant for comprehension. To investigate this question, we studied the effects of a secondary task on the processing of hand- and foot-related nouns. The secondary task occupied either the hand or the foot system, thereby impeding hand- or foot-related simulations, respectively. Participants performed a lexical decision task by responding to the presented nouns with their left hand or foot, depending on the color of the words, while withholding their response to pseudowords. In half of the experimental blocks, participants performed a simultaneous tapping task with their right hand (Experiment 1) or foot (Experiment 2). If simulations are functionally relevant for comprehension, the secondary task should affect the processing of hand words to a larger degree than the processing foot words in Experiment 1 and vice versa in Experiment 2. In both experiments, hand responses were faster for hand words than foot words, whereas the opposite was true for foot responses. This finding indicates that participants indeed simulated the words' meanings. Importantly, there was no difference between the influence of the hand tapping and the foot tapping task on lexical decision times to hand and foot words, indicating that experiential simulation might just be an optional by-product of language processing.